Airtight bag



Dec. 1, 1936 STERLING 2,062,618

AIR'IIGHT BAG Filed Nov. 27, 1931 2 Shee'ts-Sheet l INVENTOR .ATTORNE Y Dec. 1, 1936. A. J. STERLING AIRTIGHT BAG Filed Nov. 27, 1931 2 Sheets-Sheet 2 INVENTOR BY ATTORNEY Patented Dec. 1, 1936 v UNITED s'rA'ras.

PATENT OFFICE AIBTIGHT BAG Albert J. Sterling, Brooklyn, N. Y.

Application November 27, 1931, Serial No. 577,407 mm. (01. 229-53) It is the general object of this invention to provide an air tight and sift proof bag, preferably moisture proof, adapted to contain such materials as ground coffee which would be damaged by exposure to air or moisture. It is a further object in the provision of such a bag to provide air tight seams which will not be unduly bulky at intersection points.

The production of a sift proof, air tight, moisture proof paper bag has long been a problem. Paper itself is not wholly impervious to air and moisture. On the other hand, when paper is coated with paraflin or other moisture proof substance the resulting surface is difllcult to glue. To form the blanks with uncoated portions to permit gluing introduces 'manufacturing problems of a serious nature.

A modified cellulose material known as Cellophane, which is a regenerated cellulose sheeting, is an excellent substance from the standpoint of flexibility and air tightness but Cellophane, particularly the type that has been rendered moisture proof, cannot be glued by any commercially practicable method, especially not in such a way as to produce an airtight seam. A laminated product consisting of moisture proof Cellophane and Kraft paper has been produced which, by the present invention, may be formed into an absolutely air tight and moisture proof bag.

It is accordingly a feature of one form of the invention to form an air tight bag from a laminated sheet composed of Cellophane", preferably of a moisture proof type, adhesively attached to Kraft paper, the construction being such as to avoid the necessity of adhesively attaching contiguous "Cellophane surfaces. In accordance with this feature of the invention the use of adhesives ordinarily employed in the construction of bags, free from any contaminating effect upon the contents of the bag. ma be employed.

In another form of the invention the lining or lamination of "Cellophane" maybe replaced by a coating of lacquer applied to the surface of a sheet of paper which becomes the interior of the bag. This lacquer coating may render the bag air-tight and impervious to moisture in substan-- tially the same way as the Cellophane lining.

These and other objects and features will appear in the following detailed description of this invention taken in connection with the attached drawings.

In the drawings:

Figure l is a view of a blank comprising laminated Cellophane and Kraft paper showing cut..- ting "and score hues for its formation into .a bag.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a view of the bag, partially formed, 5 illustrating the preliminary folding of the longitudinal central seam.

Figure 4 shows the bag with the central and bottom seams complete, and illustrating the preliminary folding of the top seam. 10 Figures 5, 6 and '7 are respectively sections along the lines 5-5, 6-6 and 1-,! of Figure 4. Figure 8 shows the blank for a modified form of the-bag. 1

Figure 9 shows the modified bag with its longitudinal seam closed and its top and bottom seams open. 1

Figure 10 shows the bag with its bottom seam closed and its top seam in a preliminary-stage of folding. 20

Figure 11 is a section on the line I ll I of Figure 10. v Referring to Figure 1, the blank is shown as of geometrically symmetrical outline. It is formed with tabs 2-4 at its opposite ends and flaps 4-5 at its opposite sides. Ears 6 are provided at opposite corners of the tabs 2-3, and the flaps 4-5 are cut away at l at each end for a purpose which will later appear. The blank'is scored for folding along the lines shown in Figure 1, and is composed of a sheet of Cellophane ll, preferably moisture-proof, adhesively attached to a sheet of Kraft paper l2 (Fig. 2).

The bag proper will be formed from the material lying betweenlines l5-l5. The portion between lines l|ll will form the back of the bag and the portions between lines It and I 5 will each formapproximately half of the front of the bag. The first folding action brings the bag to the condition shown in Fig. 3, with the Kraft paper I! on the outside and the "Cellophane" ll forming a lining. The flaps 4 and 5 are brought into abutting relationship with their Cellophane" surfaces in contact. The flaps 4-! are then folded over against one of the portions 20. The whole seam is then folded along the lines I! to the condition shown in'Fig. 5. It will be noted that this last fold brings a paper surface of the seam material'into contact with a paper surface of the bag material and these surfaces are glued together as indicated at 2| on Fig.5.

Referring to Figs. 8, 4, 6 and 7, it will be noted that the formation of the longitudinal seam brings the cut-out portions 1 ofthe flaps 4-8 55 to the inner fold lines I! (Fig. 1) of the bag ends. The tabs-2 and 3 are now folded over along the lines 22, the ears-6 serving to prevent any leakage at thecorners. To avoid any necessity for attempting to glue the "Cellophane" surface of' the fiaps 2 and 3, they are folded a second time along the lines l8. This incorporates a part of portions of the longitudinal seam into the end seams, precluding any leakage at that point.

The provision of the cut-out portions I serves to" reduce the thickness of this juncture of the seams and is an important feature of this invention. The double fold arrangement brings about a paper-to-paper contact between the end seams and the body of the bag, facilitating glu ing as indicated at on Fig. 7.

From the foregoing it will be clear that an air? tight, sift proof bag is provided in which all seams are positively glued by a paper-to-paper contact, regardless of what material may be used as a lining. It will be understood that the upper end of the bag will be left open until the bag has been filled and this end will then be closed in the same way as the bottom. While particular reference has been made to the use of Kraft paper as the outer member of the laminated material, it should be clearly understoood that other forms of paper having the desired strength, flexibility, and toughness may be substituted. Other material having the air-excluding properties of Cellophane" may also be used in lieu of the layer ll.

lends itself readily to the omission of the moisture-proofing material from a suitable strip of the paper entering into the seam, as will be hereinafter explained. The blank 50 is formed simply with tabs 52 at its ends each having ears 53 similar to the ears 6 shown in Figure l. The bag is folded longitudinally along the score lines 55 to bring the sides 56 into a simple overlapping seam as shown in Figure 9. The tabs 52 are then double folded precisely in the manner of the fiaps 6 in the bag of Figures 4, 6 and 7. If desired the longitudinal seam may be improved somewhat by leaving a narrow strip, say half an inch or so in width, adjacent one'edge of the sheet unlacquered so that no interference is oflered to the proper faction of the glue or other adhesive.

Thus this narrow, unlacquered stripon the under surface of the outermost side 56 will provide a paper-to-paper contact with the outer surface of the other side 56.

While two specific forms have been illustrated, it is obvious that various changes could be made in the structural detafls .without departing from the spirit and scope of this invention. It is therefore not intended that the specific disclosure shall be taken to limit the invention but that it shall be regarded aslimited. only as indicated in the claims.

What I claim is:

1. A bag having an air-tight lining, a doublefolded longitudinal seam, and the ends of the bag doubly folded transversely of said seam, the material forming one of the folds of the longitudinal seam being cut out for a short distance from each end of the seam, whereby the material of only one fold of the seam is included in the end folds.

2. A bag formed from a tube having an air tight lining, each end of the tube havinga cutout portion on. one side leaving ear portions connecting the bottom of the cutout with the free edge of the other side of the tube, the ends of the tube being folded along the line of the bottom of the cutout and those folds being folded over again.

3. A bag as set forth in claim 1 including a doubly folded longitudinal seam on the tube, a portion of said seam being included inthe end folds.

4. A bag as set forth in claim 1 in which the end folds are glued to the bag.

5. A bag as set forth in claim 1 including adoubly folded longitudinal seamon the tube, the material forming one fold of the seam being cut away for a short distance from each end of the seam, whereby the end folds include the material of only one fold of the seam.

6. A bag having a paper exterior and an airtight and moisture-proof lining, with a double folded longitudinal seam and a double folded end seam transverse to the longitudinal seam, the material forming one of the folds in the longitudinal seam being cut out a short distance from the end of the seam whereby the material of only one fold of the longitudinal seam is included in the end scam, the double folding in both said seams bringing paper on the underside of each double fold in contact with the paper exterior of the bag, and said contacting paper surfaces being glued together whereby to hold the folds against opening and render the seams air-tight and moisture-proof.

All-BERT J. STERLING. 

